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Message-ID: <20091214080201.466a8998@infradead.org>
Date: Mon, 14 Dec 2009 08:02:01 -0800
From: Arjan van de Ven <arjan@...radead.org>
To: Oliver Neukum <oliver@...kum.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...e.hu>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Thomas Gleixner <tglx@...utronix.de>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
Andrew Morton <akpm@...ux-foundation.org>,
Greg KH <gregkh@...e.de>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
linux-kernel@...r.kernel.org
Subject: Re: [GIT PATCH] TTY patches for 2.6.33-git
On Mon, 14 Dec 2009 11:39:48 +0100
Oliver Neukum <oliver@...kum.org> wrote:
> Am Montag, 14. Dezember 2009 06:30:15 schrieb Arjan van de Ven:
> > > We have the bkl tracepoints for that, attaching an example below,
> > > blkdev_get/bkldev_put is among the highest consumer for me.
> >
> > we have a trace, but not a number that anyone can just pull out
> > without having to go through great lengths to set stuff up... (esp
> > to capture a boot)...
> > Adding a counter always to the lock_kernel function should be fine
> > instead...
>
> But don't we need to know how long it is held? If you just count
> you'll make code that drops it while it can look bad.
I think/hope we're well past that. At this point, just the act of taking
it at all is bad.
--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org
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